document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=611080>Question 611080</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Bob owns a watch repair shop. he has found that the cost of operating his shop is given by<BR>\n" );
document.write( " c=3x^2-216x+64, where c is the cost in dollars, and x is the number of watches repaired. how many watches must he repair to have the lowest cost?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #384778 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=384778\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Bob owns a watch repair shop. he has found that the cost of operating his shop is given by c=3x^2-216x+64, where c is the cost in dollars, and x is the number of watches repaired. how many watches must he repair to have the lowest cost?<BR>\n" );
document.write( ".<BR>\n" );
document.write( "examining:<BR>\n" );
document.write( "c=3x^2-216x+64<BR>\n" );
document.write( "we see that it is a parabola that opens upwards (by looking at the coefficient associated with the x^2 term).  Therefore, the vertex defines the minimum:<BR>\n" );
document.write( "x = -b/(2a)<BR>\n" );
document.write( "x = -(-216)/(2(3))<BR>\n" );
document.write( "x = 216/6<BR>\n" );
document.write( "x = 36 watches<BR>\n" );
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